Two quick (and probably obvious) points:

- You can do multiple simultaneous reclamations if you have multiple
storage pools.  Long on tape drives?  Create another domain (& storage
pool(s)) and split your nodes between them.

- MOVE DATA (tape to tape, or tape back to disk) allows multiple
simultaneous processes on one storage pool and each is often faster than
 the corresponding reclamation.  The down-side to MOVE DATA is that
aggregates are not reconstructed, so your newly filled tape will
immediately have reclaimable space.  Perhaps a statistician could tell
us the expected wasted space remaining after a MOVE DATA.  Maybe with
too many caveats to be useful, ... but when I switched from exclusively
performing MOVE DATAs to exclusively performing reclamation, I "gained"
almost 20% empty volumes.

cheers, wayne

Wayne T. Smith, ADSM AT Maine DOT edu, University of Maine System